This revolver is listed/documented by its serial number in the "Standard Catalog of Smith & Wesson" by Jim Supica & Richard Nahas on page 91 and in "Smith & Wesson American Model" by Charles Pate on page 192 as one of the 1,000 Model 3s that was purchased by the U.S. government in 1871. Compounding the significance of this revolver is the rarely observed oil hole (located on the rear of the extractor housing on the bottom of the barrel lug) as found on the first 1,500 or so of this model. The barrel rib has the one-line S&W address/patent dates marking followed by "US." The frame carries the desirable U.S. Orville W. Ainsworth sub-inspector's "A" initial on the left side and a "P" proof on the right side next to the recoil shield. An additional "P" proof is marked on the right side of the barrel forward the hinge. An additional Ainsworth "A" is stamped on the left side of the top strap. A script letter "OWA" inspector's cartouche is marked on the left grip panel. The right grip panel is numbered to the gun. Matching assembly marks are found on the grip frame, cylinder, barrel, and barrel latch. The revolver is pictured and identified in Dean Boorman's "The History of Smith & Wesson Firearms" on pages 1 and 106 and was displayed at the NRA Single Action Shooting Society exhibit in 2015. The S&W American Model was the first cartridge revolver adopted by the U.S. military and saw use in the Indian Wars as it was reported to have been issued to the 2nd, 3rd, 4th, 5th, 6th, and 7th Cavalry. Surviving examples of U.S. martial Model 3 Americans, especially early production oil hole examples, are scarce and highly desirable in any condition. Provenance: The Supica Collection